Circulating histones as potential biomarkers of MASLD-MASH-HCC progression

Background: Reliable biomarkers are warranted to identify patients with metabolic dysfunction-associated steatotic liver disease (MASLD), including metabolic dysfunction-associated steatohepatitis (MASH), at risk for developing hepatocellular carcinoma (HCC). Research and methods: We evaluated whether circulating histones can predict this risk. Plasma histones were measured using imaging flow cytometry in patients with MASLD (n = 25), MASH (n = 25), HCC (n = 40), and 30 healthy controls. Results: We detected (p < 0.05), compared to controls: 1) elevated levels of H2A, H3, H2A/H2B/H3/H4, macroH2A1.1, macroH2A1.2 in MASLD/MASH and HCC; 2) decreased levels of macroH2A1.2/H2B/H3/H4 in MASLD/MASH and increased in HCC; 3) reduced H4 levels discriminating between MASH and non-MASH. Machine-learning analysis showed that being diabetic/dyslipidemic, having decreased H2A (p = 0.002) and H4 (p = 0.0156) levels favor MASH. Conclusions: Our data indicate plasma histones H2A and H4 as new biomarkers of liver disease progression. The identification of histone-based biomarkers using imaging flow cytometry could provide a rapid approach to discriminate between non-MASH and MASH, and to predict the risk of HCC development.